Deployments of Apache Solr 5.3.0 through 9.10.0 that rely on Solr's "Rule Based Authorization Plugin" are vulnerable to allowing unauthorized access to certain Solr APIs, due to insufficiently strict input validation in those components. Only deployments that meet all of the following criteria are impacted by this vulnerability:
* Use of Solr's "RuleBasedAuthorizationPlugin"
* A RuleBasedAuthorizationPlugin config (see security.json) that specifies multiple "roles"
* A RuleBasedAuthorizationPlugin permission list (see security.json) that uses one or more of the following pre-defined permission rules: "config-read", "config-edit", "schema-read", "metrics-read", or "security-read".
* A RuleBasedAuthorizationPlugin permission list that doesn't define the "all" pre-defined permission
* A networking setup that allows clients to make unfiltered network requests to Solr. (i.e. user-submitted HTTP/HTTPS requests reach Solr as-is, unmodified or restricted by any intervening proxy or gateway)
Users can mitigate this vulnerability by ensuring that their RuleBasedAuthorizationPlugin configuration specifies the "all" pre-defined permission and associates the permission with an "admin" or other privileged role. Users can also upgrade to a Solr version outside of the impacted range, such as the recently released Solr 9.10.1.
CVSS Score
8.2
EPSS Score
0.002
Published
2026-01-21
The "create core" API of Apache Solr 8.6 through 9.10.0 lacks sufficient input validation on some API parameters, which can cause Solr to check the existence of and attempt to read file-system paths that should be disallowed by Solr's "allowPaths" security setting https://https://solr.apache.org/guide/solr/latest/configuration-guide/configuring-solr-xml.html#the-solr-element . These read-only accesses can allow users to create cores using unexpected configsets if any are accessible via the filesystem. On Windows systems configured to allow UNC paths this can additionally cause disclosure of NTLM "user" hashes.
Solr deployments are subject to this vulnerability if they meet the following criteria:
* Solr is running in its "standalone" mode.
* Solr's "allowPath" setting is being used to restrict file access to certain directories.
* Solr's "create core" API is exposed and accessible to untrusted users. This can happen if Solr's RuleBasedAuthorizationPlugin https://solr.apache.org/guide/solr/latest/deployment-guide/rule-based-authorization-plugin.html is disabled, or if it is enabled but the "core-admin-edit" predefined permission (or an equivalent custom permission) is given to low-trust (i.e. non-admin) user roles.
Users can mitigate this by enabling Solr's RuleBasedAuthorizationPlugin (if disabled) and configuring a permission-list that prevents untrusted users from creating new Solr cores. Users should also upgrade to Apache Solr 9.10.1 or greater, which contain fixes for this issue.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-01-21
Relative Path Traversal vulnerability in Apache Solr.
Solr instances running on Windows are vulnerable to arbitrary filepath write-access, due to a lack of input-sanitation in the "configset upload" API. Commonly known as a "zipslip", maliciously constructed ZIP files can use relative filepaths to write data to unanticipated parts of the filesystem.
This issue affects Apache Solr: from 6.6 through 9.7.0.
Users are recommended to upgrade to version 9.8.0, which fixes the issue. Users unable to upgrade may also safely prevent the issue by using Solr's "Rule-Based Authentication Plugin" to restrict access to the configset upload API, so that it can only be accessed by a trusted set of administrators/users.
CVSS Score
5.4
EPSS Score
0.03
Published
2025-01-27
Core creation allows users to replace "trusted" configset files with arbitrary configuration
Solr instances that (1) use the "FileSystemConfigSetService" component (the default in "standalone" or "user-managed" mode), and (2) are running without authentication and authorization are vulnerable to a sort of privilege escalation wherein individual "trusted" configset files can be ignored in favor of potentially-untrusted replacements available elsewhere on the filesystem. These replacement config files are treated as "trusted" and can use "<lib>" tags to add to Solr's classpath, which an attacker might use to load malicious code as a searchComponent or other plugin.
This issue affects all Apache Solr versions up through Solr 9.7. Users can protect against the vulnerability by enabling authentication and authorization on their Solr clusters or switching to SolrCloud (and away from "FileSystemConfigSetService"). Users are also recommended to upgrade to Solr 9.8.0, which mitigates this issue by disabling use of "<lib>" tags by default.
CVSS Score
5.5
EPSS Score
0.002
Published
2025-01-27
Improper Authentication vulnerability in Apache Solr.
Solr instances using the PKIAuthenticationPlugin, which is enabled by default when Solr Authentication is used, are vulnerable to Authentication bypass.
A fake ending at the end of any Solr API URL path, will allow requests to skip Authentication while maintaining the API contract with the original URL Path.
This fake ending looks like an unprotected API path, however it is stripped off internally after authentication but before API routing.
This issue affects Apache Solr: from 5.3.0 before 8.11.4, from 9.0.0 before 9.7.0.
Users are recommended to upgrade to version 9.7.0, or 8.11.4, which fix the issue.
CVSS Score
9.8
EPSS Score
0.941
Published
2024-10-16
Insecure Default Initialization of Resource vulnerability in Apache Solr.
New ConfigSets that are created via a Restore command, which copy a configSet from the backup and give it a new name, are created without setting the "trusted" metadata.
ConfigSets that do not contain the flag are trusted implicitly if the metadata is missing, therefore this leads to "trusted" ConfigSets that may not have been created with an Authenticated request.
"trusted" ConfigSets are able to load custom code into classloaders, therefore the flag is supposed to only be set when the request that uploads the ConfigSet is Authenticated & Authorized.
This issue affects Apache Solr: from 6.6.0 before 8.11.4, from 9.0.0 before 9.7.0. This issue does not affect Solr instances that are secured via Authentication/Authorization.
Users are primarily recommended to use Authentication and Authorization when running Solr. However, upgrading to version 9.7.0, or 8.11.4 will mitigate this issue otherwise.
CVSS Score
8.1
EPSS Score
0.002
Published
2024-10-16
CVE-2023-44487
The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.
Known exploited
CVSS Score
7.5
EPSS Score
0.944
Published
2023-10-10